JP2014048144A - Unit for performing evaluation test on tabular test piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a unit for evaluating material strength of a thin metal plate, the unit being suitable for high-temperature creep test or tensile test of a thin metal plate.SOLUTION: A unit 1 for evaluating high-temperature creep strength comprises a tabular test piece 2 and a pair of fixing jigs 3 for attaching the test piece 2 to a chuck of a test device. The thin test piece 2 and the jigs 3 are configured to be integrally fixed by a fixing pin 4. The test piece 2 has shoulders 22 fitted to and stored in shoulder fitting grooves 34 of the jigs 3 and has a parallel part 21 partially fitted to and stored in a slit 33. In this state, the fixing pin 4 is inserted to a through hole 25 to have the position fixed, whereby the unit 1 for evaluation is configured. Next, the unit 1 is erected, and upper and lower ends of a grip 31 is engaged with and fixed to a pull rod 5 of the test device. Further, ring-shaped projections 35 of the upper and lower jigs 3 are fixed to an upper jig 6a and a lower jig 6b of a jig 6 for measurement, respectively. After the completion of attachment, the parallel part 21 in the unit 1 is stored in an electric oven 7.

Description

  The present invention relates to a unit for evaluating material strength of a thin metal plate, and more particularly to a unit for evaluating material strength of a thin metal plate suitable for a high temperature creep test or tensile test.

  Conventionally, as a test piece used for a high temperature creep test of a metal material, a circular cross-section (bar-shaped) test piece having a diameter of 3 mm or more described in JIS Z2271 (Document 1) is used. In measuring creep elongation, a round cross-section test piece with a flange and a groove shown in the appendix of the same document is used. FIG. 5A shows such a circular cross-section test piece 100, which includes grip portions 102 at both ends of the parallel portion 101, a ridge 103 on both sides of the parallel portion 101, and a groove portion 104 in the grip portion 102.

  However, there is no JIS regulation on the shape of the test piece for the material strength test such as creep using a plate-shaped test piece for the purpose of evaluating a thin metal plate. For this reason, based on the metal material tensile test piece of JIS Z2201 (Document 2), which is a standard for a tensile test of a thin metal plate, the measurer devised and evaluated it with reference to the JIS Z2271.

  Specifically, as shown in FIG. 5B, a rod-shaped pin (not shown) is fixed in the pin insertion hole 203 provided in the shoulder portion 202 of the plate-shaped test piece 200 and fixed to the pin. Weigh and measure the elongation. When the plate thickness is relatively thick, a gage 204 is provided in the parallel part so that the standard test apparatus for the circular cross-section test piece 100 described above can be used, and a measuring jig is connected to the gage 204. And measure the elongation.

JIS Z 2271 (Creep and creep rupture test method for metal materials) JIS Z 2201 (Metal material tensile test piece)

However, since a large stress is applied to the pin insertion hole 203 in the test piece 200 of FIG. 5B, the insertion hole 203 and its surroundings are locally deformed unless the cross-sectional area of the parallel portion 201 is reduced. There is a problem that creep evaluation cannot be performed correctly.
In addition, the method of connecting the elongation measuring jig to the gauge point 204 also has a problem that when the test piece is thin, the mechanical strength is insufficient and the measuring jig cannot be supported.
On the other hand, as a measurement method when the plate thickness is thin, deformation measurement by image analysis using a laser displacement meter, a camera, etc. is also used, but despite the necessity of a very expensive dedicated test device. However, there is a problem that the measurement accuracy is not necessarily high.

In view of the above problems, the present invention provides a plate-shaped test piece evaluation unit constituted by a plate-shaped test piece and a jig for the purpose of evaluating a thin metal plate.
The gist of the present invention is as follows. That is, the plate-shaped specimen evaluation unit according to the present invention is
A test piece material strength evaluation unit comprising a thin plate-shaped test piece, and a pair of fixing jigs for attaching both ends of the test piece to a test apparatus,
The specimen is
A thin metal plate to be evaluated, having a parallel portion at the center portion and shoulders wider than both ends of the parallel portion;
A fixing jig fitting portion configured in a wedge shape in cross section, which is integrally fixed to the metal thin plate on both sides of the shoulder portion and fitted and fixed to the receiving groove portion of the fixing jig,
The fixing jig is
A grip for fixing to the test device pull rod;
An elongation measuring jig mounting portion configured to be capable of mounting an elongation measuring jig;
It is characterized by comprising a test piece accommodation groove for accommodating a test piece fixing jig fitting part and a part of the parallel part in close contact with each other.

According to the present invention, it is possible to reliably attach the test device test piece to the standard test device, to reduce the load for the test, and to ensure the objectivity of the evaluation.
Moreover, even if the cross-sectional area of the parallel part of the test piece is not small, there is an effect that local concentration of stress in the vicinity of the pin can be avoided.
Further, there is an effect that the elongation measurement accuracy in the creep test can be improved without using an expensive dedicated test device such as a laser displacement meter.

It is a figure which shows the whole structure of the unit 1 for plate-shaped test piece evaluation which concerns on one Embodiment of this invention. FIG. 3 is a diagram showing a configuration of a test piece 2. FIG. 3 is a diagram showing a planar configuration of a test piece 2. It is a figure which shows the A-A 'cross-section structure of FIG.2 (b). FIG. 3 is a diagram illustrating a planar configuration of a fixing jig 3. It is a figure which shows the B-B 'cross-section structure of Fig.3 (a). It is a figure which shows the state which attached the unit 1 for test piece evaluation to the test apparatus. FIG. 3 is a diagram schematically showing a load applied to a test piece 2. It is a figure which shows the structure of the circular cross-section test piece 100 prescribed | regulated to JISZ2271. It is a figure which shows the structure of the conventional plate-shaped test piece 200. FIG.

  Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 4B. Needless to say, the scope of the present invention is described in the claims and is not limited to the following embodiments.

  FIG. 1 is a diagram showing an overall configuration of a high-temperature creep strength evaluation unit 1 (hereinafter, appropriately abbreviated as unit 1) of a plate-shaped test piece according to an embodiment of the present invention. The unit 1 includes a plate-shaped test piece 2 and a pair of fixing jigs 3 for attaching the test piece 2 to a pull rod 5 (see FIG. 4A) of the test apparatus. The thin test piece 2 and the jig 3 are configured to be integrally fixed by a fixing pin 4.

  2 (a) to 2 (c), the test piece 2 includes a metal thin plate 23 having a parallel portion 21 and wide shoulder portions 22 at both ends thereof, and a shoulder portion 22 of the metal thin plate 23. And fixing jig fitting portions 24 that are fixed to both side surfaces by welding. The parallel part 21 is a part to be subjected to strength evaluation, and the shoulder part 22 is a part fitted and fixed to the jig 3. The shoulder portion 22 is provided with a through hole 25 through which the fixing pin 4 is inserted through the thin metal plate 23 and the fixing jig fitting portion 24.

  Referring to FIGS. 3 (a) and 3 (b), the fixing jig 3 has a substantially bottle-shaped outer shape, a cylindrical grip 31 for attaching to the pull rod 5 of the test apparatus, and a smaller size than this. It is comprised by the jig | tool attachment part 32 for elongation measurement of a cylindrical shape of a diameter. In the center of the grip portion 31, a shoulder fitting groove 34 having the same shape as the cross section of the shoulder portion 24 of the test piece 2 and capable of fitting and accommodating the same is provided. Further, a female screw 37 for screwing and fixing the pull rod 5 is provided. Furthermore, a through hole 36 is provided through which the fixing pin 4 for integrally fixing the test piece 2 when fitted and received is inserted.

  A ring-shaped protrusion 35 for fixing the measurement jig 6 is provided around the outside of the measurement jig attachment portion 32. Moreover, the slit 33 which reaches the shoulder part fitting groove | channel 34 along the central axis is provided, and the parallel part 21 of the test piece 2 is comprised so that fitting accommodation is possible.

The unit 1 is configured as described above. Next, an aspect of attaching the unit 1 to the standard test apparatus will be described.
2A and 4A, the shoulder portion 22 of the test piece 2 is fitted and accommodated in the shoulder portion fitting groove 34 of the jig 3, and a part of the parallel portion 21 is fitted and accommodated in the slit 33. Let In this state, the fixing pin 4 is inserted into the through hole 25 and fixed in position, and the evaluation unit 1 is configured.

Next, the unit 1 is put upright, and the upper and lower ends of the grip portion 31 are screwed and fixed to the pull rod 5 of the test apparatus. Further, the ring-shaped protrusions 35 of the upper and lower jigs 3 are fixed to the upper jig 6a and the lower jig 6b of the measurement jig 6, respectively. Although not shown in the figure, a strain gauge is connected to the lower end of the measuring jig 6, and the amount of strain is detected based on the positions of the upper jig 6a and the lower jig 6b before and after the test, and the creep amount is evaluated. It is configured to be possible.
After the attachment is completed, the parallel part 21 of the unit 1 is accommodated in the electric furnace 7 to complete the attachment to the test apparatus.

A load is applied to the evaluation unit 1 while the electric furnace 7 is maintained at a predetermined test temperature, the output of the strain gauge connected to the measuring jig 6 is amplified by an amplifier, and then taken into a PC using an analog / digital converter. Measure the creep amount.
Referring to FIG. 4 (b), according to the present invention, the load from the test apparatus is such that the fixture fitting portion 24 for fixing the test piece 2 (see FIG. 2 (b)) and the shoulder fitting groove 34 (see FIG. 4). 3 (see (b)), and the load is not applied to the contact surface between the fixing pin 4 and the through hole 25. For this reason, stress concentration does not occur in the pin vicinity portion (shoulder portion 22) of the test piece 2. The cross-sectional area of the parallel portion 21 can be set as appropriate in accordance with the magnitude of the load, the area of the contact surface of the shoulder fitting groove 34, and the angle φ formed between the central axis and the fitting portion 24. .

  The present invention can be applied as a test piece evaluation test unit for a tensile test and creep test apparatus for a general sheet metal material.

DESCRIPTION OF SYMBOLS 1 ... Unit for plate-shaped test piece evaluation 2 ... Plate-shaped test piece 21 ... Parallel part 22 ... Shoulder part 23 ... Metal thin plate 24 ... Fixing jig fitting part 25... Through hole 3... Fixing jig 31... Grip part 32... Jig mounting part for measurement 33. Slit 34. Protrusion 36 ... through hole

Conventionally, as a test piece used for a high temperature creep test of a metal material, a circular cross-section (bar-shaped) test piece having a diameter of 3 mm or more described in JIS Z2271 (Document 1) is used. And when creep elongation measurement, flange-grooved circular cross section specimen shown in this document Annex is used. FIG. 5A shows such a circular cross-section test piece 100, which includes grip portions 102 at both ends of the parallel portion 101, a ridge 103 on both sides of the parallel portion 101, and a groove portion 104 in the grip portion 102.

Claims (1)

A test piece material strength evaluation unit comprising a thin plate-shaped test piece, and a pair of fixing jigs for attaching both ends of the test piece to a test apparatus,
The specimen is
A thin metal plate to be evaluated, having a parallel portion at the center portion and shoulders wider than both ends of the parallel portion;
A fixing jig fitting portion configured in a wedge shape in cross section, which is integrally fixed to the metal thin plate on both sides of the shoulder portion and fitted and fixed to the receiving groove portion of the fixing jig,
The fixing jig is
A grip for fixing to the pull rod of the test device;
An elongation measuring jig mounting portion configured to be capable of mounting an elongation measuring jig;
A test piece housing groove for accommodating a jig fitting part for fixing the test piece and a part of the parallel part in close contact with each other,
A test piece evaluation test unit characterized by comprising:

Images